The objectives of the proposed research are to explore the effects of delta 9-THC on the withdrawal phase of ethanol dependence in mice and to establish if cross-tolerance forms between ethanol and delta 9-THC. The determination of the effects of delta 9-THC on ethanol withdrawal will be accomplished by making mice dependent upon ethanol by exposing them to ethanol vapor for a period of 3 days. Following the development of dependence, the animals will be removed from the chamber and the effects of delta 9-THC on withdrawal symptoms will be determined. The determination of the development of cross-tolerance between delta 9-THC and ethanol would first involve the development of tolerance to each of these agents. Mice would receive daily injections of delta 9-THC and ethanol followed by motor coordination tests on a rotarod apparatus. When tolerance to the disruptive effects of delta 9-THC and ethanol on rotarod performance has developed, delta 9-THC tolerant animals would receive ethanol and ethanol tolerant animals would receive delta 9-THC, and rotarod performance subsequently examined.